[flang-commits] [flang] [flang] Inline scalar-to-scalar TRANSFER for same-size trivial types (PR #191589)

[via flang-commits]

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@@ -8680,6 +8680,38 @@ IntrinsicLibrary::genTransfer(mlir::Type resultType,
 
   assert(args.size() >= 2); // args.size() == 2 when size argument is omitted.
 
+  bool absentSize = (args.size() == 2);
+
+  // Inline scalar-to-scalar transfers when the result is a trivial type
+  // (integer, real, etc.) and both source and result have the same storage
+  // size.
+  if (absentSize && fir::isa_trivial(resultType)) {
+    mlir::Value sourceBase = fir::getBase(args[0]);
+    mlir::Type sourceType = fir::unwrapRefType(sourceBase.getType());
+    mlir::Type moldType = fir::unwrapRefType(fir::getBase(args[1]).getType());
+    if (fir::isa_ref_type(sourceBase.getType()) &&
+        !mlir::isa<fir::SequenceType>(sourceType) &&
+        !mlir::isa<fir::SequenceType>(moldType)) {
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jeanPerier wrote:

A positive checks with `fir::isa_trivial(sourceType) && fir::isa_trivial(moldType)` would be more restrictive and ensure the code is not relying on too many invariants about what `sourceBase` and the mold mlir types (just for the future sake, I do no think there is any bug with your code currently).

https://github.com/llvm/llvm-project/pull/191589